I also tend to find most dark web designs (which is what a lot of these comments are talking about) just plain ugly. So, that's another factor. I've never made a dark website or web UI.
All of this is opinion, of course. My opinion should probably matter less than someone that really cares a lot about it.
I think it's silly because I think the way so many people approach web design is silly. Standardized UI components are not a bad thing. They are a very good thing. I like it when web pages look like they belong on my computer screen.
It's not only dark web designs. Actually if you look at any native application on your OS you will see "styled" scrollbars. And that never shocked you because they are styled according to the app.
> I like it when web pages look like they belong on my computer screen.
This is what "view > page style > no style" is for.
CSS was created to "style" page, and the scrollbar is part of the page. That you like CSS or not it seems silly to say that the scrollbar is the limit where you can style everything BUT the scroll bar on a page.
The page designer has no control over the display size.
But if you scroll the same websites in Firefox (which is my main browser), those will stand out. It's not only the scrollbar of the page, it's also any scrollbar that you can see inside a iframe or a textarea or really any divs with overflow:scroll;
If you think this is silly then you must think CSS and styling page is silly